The use of non-azeotropic fluid mixtures in a heat pump, in order to improve the performance coefficient of the heat pump, has been the object of prior U.S. patents and (U.S. Pat. No. 4,089,186; U.S. Pat. No. 4,344,292, No. 227,844 filed Jan. 23, 1981 and No. 339,565 filed Jan. 15, 1982).
More specifically, U.S. patent application No. 226,984 describes the use of non-azeotropic mixtures of two constituents capable of increasing the performance of a heat pump and thus, to decrease the operating cost of said heat pump. The two constituent mixtures described therein do not increase, however, the thermal power of a given compressor.
Other mixtures of working fluids are disclosed in the following patents:
GB Pat. No. 1,063,416 discloses a mixture of R 13, i.e., chlorodifluoromethane with R 23, i.e., monochlorodifluoromethane, useful at a low refrigeration temperature. PA0 EP Pat. No. 0,011,971 discloses a mixture of R 22, i.e., monochlorodifluoromethane, with R 32, i.e. difluoromethane. PA0 U.S. Pat. No. 3,487,653 discloses a mixture of R 12, i.e., dichlorodifluoromethane, R 22 or R 502, i.e., a mixture of 48.8% b.w. chlorodifluoromethane and 51.2% b.w. chloropentafluoromethane with either R 13 or R 503, i.e., a mixture by weight of 40.10% trifluoromethane and 59.9% chlorotrifluoromethane. The proportions are selected to operate at a temperature lower than -65.degree. C. PA0 U.S. Pat. No. 2,255,585 discloses a large number of refrigerant mixtures.